In a word....no. The metrorail runs from down near Reliant Plaza (where the Astrodome and Reliant Stadium are) past the Medical Center into downtown. Althought there are some bars and restaurants downtown, most of the nighttime action in Houston is out in the Richmond-Westheimer-Galleria area and metrorail doesn't go there. If you're going to a concert, play, Astros or Rockets game, it's a decent way to get around downtown. Otherwise, rent a car or take a cab.
By the way, the best titty bars in the entire world are in Houston, Texas. Classy and plush clubs with gorgeous women. Bring plenty of cash if you go.